Efficacy of flow diversion in blister-like intracranial aneurysms during acute subarachnoid hemorrhage: a single-arm meta-analysis

Background Blister-like intracranial aneurysms are rare fragile lesions with a high risk of rupture leading to acute subarachnoid hemorrhage (aSAH) and significant morbidity. Flow diversion (FD) has emerged as a promising endovascular treatment, particularly for complex cases unsuitable for clipping or coiling, but evidence in ruptured settings remains limited due to challenges such as the risks of dual antiplatelet therapy. This study aimed to evaluate the efficacy and safety of FD in ruptured blister-like aneurysms during aSAH through a systematic review and meta-analysis. Methods A single-arm meta-analysis was conducted following PRISMA guidelines, searching Medline, Web of Science, Embase, and Cochrane Library from inception to the present. Inclusion criteria were patients of any age with acutely ruptured blister-like aneurysms treated with FD, focusing on occlusion rates, complications, rebleeding, retreatment, modified Rankin Scale (mRS) scores, and mortality. Data were analyzed using a random effects model, with heterogeneity assessed by I² and quality evaluated using the Newcastle–Ottawa Scale. Results Twenty observational studies (n=209 patients) were included. The mean age was 50.7 years and 60.7% were women. Follow-up occlusion reached 83% (95% CI 0.72 to 0.94; I²=86%), while immediate occlusion was 37% (95% CI 0.18 to 0.55; I²=92%). Functional outcomes showed 91% had an mRS score of 0–2 at follow-up (95% CI 0.86 to 0.96; I²=0%) and 64% at discharge (95% CI 0.32 to 0.96; I²=96%). Complications were 9% intraprocedural (95% CI 0.04 to 0.15; I²=36%) and 6% postprocedural (95% CI 0.01 to 0.11; I²=0%), with rebleeding at 2% (95% CI 0.00 to 0.06; I²=0%) and mortality at 2% (95% CI 0.00 to 0.06; I²=0%). Sensitivity and publication bias analyses confirmed the stability of the results. Conclusions FD achieves high occlusion and favorable functional outcomes in ruptured blister-like aneurysms, although immediate occlusion and complications pose challenges. Future research should optimize antiplatelet strategies and standardize protocols.